1. Field of the Art
This invention relates to a direct-acting electromagnetic valve which is arranged to drive a valve body directly from an electromagnetic drive, and more particularly to a balanced type direct-acting electromagnetic valve in which fluid pressures are applied to the opposite ends of a valve body in a balanced state.
2. Prior Art
In the direct-acting electromagnetic valves which are arranged to drive a valve body directly by means of an electromagnetic drive, it is desirable to balance the fluid pressures to be applied to the opposite ends of a valve body for the purpose of securing smooth movements of the valve body in operation.
In this regard, Japanese Laid-Open Patent Application 61-096272 proposes a balanced type direct-acting electromagnetic valve, having chambers at the opposite ends of a valve body intercommunicated with each other by way of an axial hole formed internally of the valve body and having one of the chambers directly communicated with an exhaust port.
According to the just-mentioned prior art electromagnetic valve, the fluid pressures prevailing in the chambers at the opposite ends of the valve body are balanced with each other through the intercommunicating axial through hole in the valve body, so that the position of the valve body can be switched relatively easily. In this case, however, the valve body is slidably supported in a valve bore only in part of its intermediate portion and disposed in a completely free state at its axially opposite end portions. This gives rise to problems such as inclinations or instable movements of the valve body which might take place while it is in movement for a switching operation. The inclinations of the valve body will result in scratchy contact of the valve body with the walls of the valve bore, causing malfunctioning in switching operations due to the instable staggering motions of the valve body or shortening the service life of the electromagnetic valve itself to a considerable degree.